Tamper-resistant marker and method of mounting same

ABSTRACT

A tamper-resistant marker is formed of metal sheet material from a substantially planar blank thereof having a perimeter and two faces. The marker has a flange extending therefrom about the perimeter in a direction substantially perpendicular to the faces. The marker also has indicia with raised portions on one of the two faces, the raised portions being raised in a direction opposite to that of the flange. Methods of manufacturing the marker and of mounting it on a surface are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application based on U.S. patent application Ser.No. 10/923,972, filed Aug. 23, 2004.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the marking of storm drains to alertmembers of the public to the dangers in dumping detrimental materialsinto waterways. More specifically, the invention relates to atamper-resistant marker for this purpose and to a method of mounting themarker.

2. Description of the Prior Art

The U. S. Environmental Protection Agency (EPA) has directed the statesto develop programs to educate the public about the dangers to theenvironment when materials that are harmful to the health and safety ofliving organisms are dumped into streets and driveways, eventually to bewashed to storm drains to enter rivers, streams, and other waterwaysand, possibly, our drinking water system.

The education program includes the marking of storm drains which leadfrom roadways and ultimately to waterways. Currently, several methodsare used to carry out this marking.

Firstly, stencils have been commonly used to apply a warning message tothe surface of concrete or asphalt near the storm drain. However, thepaints used typically weather poorly and have to be redone every fewyears. The spray painting itself is time consuming, and cannot be donein wet or cold weather, or in windy conditions. Moreover, the paintvapors are potentially harmful to the user. The resulting prints aremessy, and leave a message less clear than desirable.

Alternatively, ceramic tile markers, which have been screen-printed withan appropriate message and glazed, may be applied with adhesives andcemented in place. Ceramic tile markers, however, are easy to crack inuse and are expensive. Flat cast or metal markers have also been used inthe past. These have good life expectancy, but are expensive tomanufacture and difficult to read. Because of their flat backs, theyoften fail to adhere to the adhesives.

Finally, plastic domed markers are most often used to identify stormdrains. They are made of a base material, such as vinyl orpolycarbonate, screen-printed with an appropriate message, and die-cutinto shape. The resulting blank is covered with a polyurethane coatinghaving ultraviolet (UV) inhibitors to protect against damage caused byexposure to sunlight. This heavy, syrup-like coating flows to the edgeof the blank and hardens. The resulting product has graphics under aclear plastic dome that thins near the edges. Adhesives, like liquidnails, may be used to apply the markers to various surfaces.

There are several problems associated with these plastic domed markers.Firstly, exposure to direct sunlight causes embrittlement in plastics.Secondly, daily temperature variations often cause the adhesive to failon the undersurface of the marker because the flat vinyl surface issmooth and offers little bond to the adhesive. Finally, colorful, domedplastic markers are attractive and easily pried from the surfaces towhich they are attached by vandals and others who like to collect them.A penknife or small screwdriver is all that is required for thispurpose, as the plastic domed markers are flexible and can readily bepeeled from the surface to which they are applied once an edge isexposed.

The present invention is directed toward these shortcomings of the priorart and provides a tamper-resistant marker which cannot be as readilyremoved from a surface as those of the prior art.

SUMMARY OF THE INVENTION

Accordingly, the present invention is a tamper-resistant marker whichcomprises a blank made of metal sheet material. The blank issubstantially flat and has a perimeter, two faces, and a flangeextending therefrom about the perimeter in a direction substantiallyperpendicular to the faces. The blank also had indicia with raisedportions on one of the two faces. The portions in question are raised ina direction opposite that of the flange. The areas between the raisedportions may be painted to make the indicia more visible or legible, asthe case may be.

As will be discussed below, the marker is mounted on a surface bycutting a groove thereinto having the shape of the flange extendingaround the perimeter of the blank. The flange resides in the groovebelow the level of the surface when mounted, making it difficult for avandal to remove the marker.

The present invention also includes a method for manufacturing thetamper-resistant marker. The method comprises the steps of providing ablank of sheet metal, the blank having two faces and a perimeter, and ofembossing indicia having raised portions onto one of the two faces ofthe blank. The method finally includes the step of forming a flangeabout the perimeter in a direction substantially perpendicular to thefaces and in a direction opposite to that of the raised portions of theindicia.

Finally, the present invention includes a method of mounting thetamper-resistant marker on a surface. The method comprises the step ofproviding a marker having a substantially planar face and having aperimeter with a flange extending therefrom in a direction perpendicularto the face. The method also includes the step of cutting a groove intothe surface onto which the marker is to be mounted. The groove conformsto the perimeter of the marker to accommodate the flange when the markeris installed on the surface.

Finally, an adhesive is applied onto the surface within the area definedby the groove, and the marker is pressed into the adhesive with theflange disposed in the groove.

The present invention will now be described in more complete detail withfrequent reference being made to the figures identified below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a marker of the present invention;

FIG. 2 is a cross sectional view of the marker taken as indicated inFIG. 1;

FIG. 3 is a perspective view of a hole saw having a coaxial drill;

FIG. 4 is a partly cross-sectional, partly perspective view of a markerwhen installed; and

FIG. 5 is a perspective view of an installed marker.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to these figures, FIG. 1 shows a plan view of a marker 10 ofthe variety used in the practice of the present invention. FIG. 2 is anenlarged cross section thereof taken as indicated in FIG. 1.

The marker 10 is made of a metal, such as aluminum, brass or stainlesssteel, in heavy, 16-gauge (0.060-inch thick), blank sheets. Embossingdies form the flat blanks into deep three-dimensional disks or plateswith raised copy, such as that on marker 10. A high tonnage power press,rated at 400 tons, is used for this purpose. The embossing adds strengthto the metal material, often equivalent to doubling its thickness.

After embossing, the oversized plate is placed upon a blanking die thatforms a dome, drawing the sides of the blank rearward to form anapproximately 0.125-inch-deep dish- or cup-like shape just before itcuts the round blanks. The flange 12 formed in this operation is shownin FIG. 2, along with the embossed pattern 14, which is what may be seenof the design shown in FIG. 1 when viewed in cross section.

The shaped blanks, which may, for example, be 4.0-inch-diameter disks,are then deburred by sanding the cut edges or tumbling the disk in anabrasive medium.

After cleaning, the disks are placed upon an anvil nest and an abrasivepad, scotchbrite or emery cloth is rotated upon the face, to give aprism-spin appearance that reflects light and gives a high-qualityappearance to the disk. At the same time, this operation applies a fine,uniform circular scratch to the surface and background of the disk whichimproves the adhesion of paint to be applied thereon.

A baking enamel containing ultraviolet inhibitors is spray-painted ontothe surface and, while still wet, the plate is placed upon a conveyorbelt that transports the product under a series of rollers having asolvent-absorbing paper to remove the wet paint from the raised portionsof the embossed surface leaving the background in a painted andcontrasting color. Alternatively, the paint may be removed from theraised portions of the embossed surface after curing with an abrasivesanding disk.

The plate is then baked at high temperatures to cure the paint and makeit hard.

Alternatively, the flat blanks may be screen-printed with acolor-contrasting background prior to embossing in registration with thescreen-printed background. One or more colors may be applied in thismanner. The blank may also be baked prior to the embossing step in thisalternative.

The resulting finished product is distinctive, easy to read, has ahigh-quality appearance and, when compared to any other existing stormdrain marker, gives the appearance of a product of much higher cost. Theproduct with embossed-copy permanence has a life expectancy of more thanthirty years, that is, its three-dimensional copy will be readable forover thirty years, two or more times longer than other products in usetoday.

The marker 10 may be mounted onto a concrete or other surface in thefollowing manner. The surface may be a flat or plane surface, and mayalso be the curved or flat surface of a utility pole of concrete, woodor fiberglass. Referring to FIG. 3, a hole saw 20 having a diametersubstantially equal to that of the marker 10 may be used to make ashallow circular groove into the surface on which the marker 10 is to bemounted. For centering purposes, and to accommodate a bolt for securingthe marker 10 on the surface, the hole saw 20 has a drill 22 with acarbide bit 24. Using a power tool, the hole saw 20 and carbide bit 24can be used to drill a center hole, perhaps to a depth of 1.0 inch, inthe center of a circular groove having a depth nominally in a range from0.0625 to 0.125 inch into the concrete, asphalt or other surface wherethe marker 10 is to be mounted. The purpose of the circular groove is toaccommodate the flange 12 on the marker 10.

Upon completion of the drilling process, dust and chips are blown orbrushed out. An adhesive or epoxy is then applied to fill the drilledhole and the area inside the circular groove. The marker 10 is thencentered over the circular groove, lining up flange 12 therewith, andpressed down. As a consequence, the leading edge 14 or the flange 12will be below the surface of the concrete or asphalt and the marker 10will be embedded in the surface, presenting a much lower tripping hazardthan other mounting methods.

FIG. 4 is a partly cross-sectional and partly perspective view of amarker 30 having a somewhat different design from marker 10. The marker30 has been installed in the manner described above. Flange 32 isdisposed in circular groove 44, and, as such, the leading edge 34 of theflange 32 is below the surface 40 of the concrete, asphalt or othermaterial. An adhesive or epoxy 42 is used to hold the marker 30 to thesurface 40. Because the marker 30, like marker 10 described above, hasembossed areas which increase the surface area of the underside, theadhesive or epoxy 42 has increased area to bond both to the underside ofthe marker 30 and surface 40. Also shown is the optional bolt 36 whichis secured within hole 46 by adhesive or epoxy 42.

FIG. 5 is a perspective view of marker 10, which lacks a bolt 36,installed on a surface 40 of concrete, asphalt or the like. Littleadhesive or epoxy 42 may be seen around the perimeter of the marker 10.Because the flange 12 of marker 10 is within a circular groove 44 intosurface 40, an implement, such as a screw driver or penknife, cannotreach below leading edge 14 to pry the marker 10 away. When embeddedinto concrete or asphalt in this manner, a snow plow scraping the topsurface thereof will not dislodge the marker 10 as its flange 12 isfirmly mounted below the level of the surface 40.

Modifications to the above would be obvious to those of ordinary skillin the art, but would not bring the invention so modified beyond thescope of the appended claims.

1. A tamper-resistant marker comprising: a blank of metal sheetmaterial, said blank being substantially planar and having a perimeterand two faces, said blank having a flange extending therefrom about saidperimeter in a direction substantially perpendicular to said faces, saidblank further having indicia with raised portions on one of said twofaces, said raised portions being opposite in direction to said flange.2. A tamper-resistant marker as claimed in claim 1, wherein said blankis circular.
 3. A tamper-resistant marker as claimed in claim 1, whereinsaid blank is domed convexly in a direction opposite to that of saidflange.
 4. A tamper-resistant marker as claimed in claim 1, wherein saidblank is of a metal selected from the group consisting of aluminum,brass and stainless steel.
 5. A tamper-resistant marker as claimed inclaim 1, wherein said blank is 0.060 inch thick.
 6. A tamper-resistantmarker as claimed in claim 1, wherein said flange is 0.125 inch high. 7.A tamper-resistant marker as claimed in claim 1, wherein said facebearing said indicia with raised portions has a fine, uniform pattern ofcircular scratches.
 8. A tamper-resistant marker as claimed in claim 1,wherein said face bearing said indicia with raised portions is coveredwith a paint.
 9. A tamper-resistant marker as claimed in claim 8,wherein said paint is removed from said raised portions of said indicia.10. A tamper-resistant marker as claimed in claim 9, wherein said paintis removed with an abrasive sanding disk.
 11. A tamper-resistant markeras claimed in claim 8, wherein said paint includes ultraviolet (UV)inhibitors.
 12. A tamper-resistant marker as claimed in claim 1, whereinsaid face bearing said indicia with raised portions is screen-printed.